As they grow older, it seems more and more adventurous rock and pop stars of the past 30 years are turning their attentions to classical music. Whether to legitimise the latter end of a long career or to appeal to the maturing tastes of their original fans as they, too, grow up – Sting, Elvis Costello and many other rock hall-of-famers have waded into the murky waters of classical crossover with a symphony or string quartet in tow… And with varying degrees of success.

Now Deutsche Grammophon, the world’s oldest classical label, has enlisted alternative singer-songwriter Tori Amos to pen a song cycle drawing on classical themes. The result, Night of Hunters, will be released on September 23. Amos, now 48, fuelled a feminist revolution in popular music during the early 1990s with hits like Cornflake Girl and Crucify. Incisive lyrics, electrifying stage presence at the piano and sales of more than 12 million albums have secured her place in the pantheon of women in rock. She also happens to be classically trained. So why combine the genres now?

Amos explains the impetus for the project. “A musicologist at Deutsche Grammophon called Dr Alexander Burh had heard I’d been working on a musical with the British National Theatre in London. He approached me about writing a song cycle and said, ‘I think you need to open yourself up to this form’.”

Buhr became her “bridge between two worlds”, bombarding her with the Debussy preludes, Scarlatti sonatas and sundry works by Bach that became the foundation of the album. “I was grateful he was sharing these treasures with me,” she said.

Her introduction to the classical canon came much earlier. As a five-year-old budding pianist, Amos won a place at Baltimore’s prestigious Peabody Conservatory, but her consuming interest in rock and a reluctance to read sheet music led to the discontinuation of her scholarship by the time she was 11. It wasn’t until now, after more than 20 years trailblazing in alternative rock, that she felt ready to confront her classical roots. “I think it’s really dangerous doing something like this, because you have to be willing to study it and that takes a lot of discipline.

“If you’re so intimidated by working with the masters, then you need to leave; then don’t get involved. But you have to respect them.”

The singer-songwriter is quick to point out that her appropriation of familiar classical themes – far from being a shrewd crossover strategy – is simply the natural evolution of what has come before. “I feel like music sometimes gets confined to categories, but the classical world is really open right now to defining what 21st-century lieder will be. You know, you can’t just keep repeating exactly music from 150 years ago in that form and be expanding and growing as a form. Variations on a theme are a part of Europe’s classical tradition.”

Working with longtime collaborator John Philip Shenale on the lush chamber arrangements for Night of Hunters’ 14 songs, and inviting the Apollon Musagéte string quartet and the Berlin Philharmonic’s principal clarinetist to play on the album as part of an octet, Amos has treated the music with what she calls "a delicate ruthlessness", staying true to the atmosphere of the originals even as she shapes her narrative through pieces as varied as Mussorgsky’s Old Castle and Satie’s Gnossienne No 1.

Amos cites the searing emotional intensity of Winterreise as “a big guiding light” for the drama at the core of her own cycle. Rather than putting a lovelorn male protagonist through his paces, however, Night of Hunters explores a woman’s response to a relationship in crisis as she is guided through a nocturnal realm of self-discovery.

“The music came first and sculpted the story and the lyrics,” recalls Amos, who was emboldened by her classical source material to garland each song with antiquated, consciously lofty imagery. “It was clear that there needed to be a certain kind of poetry for this to work. I needed to pull on mythology – that was my friend here.”

In fact, she talks my ear off about Celtic mythology, which colours much of the spiritual journey that unfolds throughout Night of Hunters. The cycle also became a profoundly personal journey for Amos, who named her leading lady “tori” and co-opted her niece and 11-year-old daughter Natashya to sing on the album (in the respective roles of a Fire Muse and a shape-shifting fox). In the song Cactus Practice, based on a Chopin nocturne, her daughter instructs her to drink from the titular plant in some kind of hallucinogenic, peyote-fuelled ritual promoting deeper understanding.

If that all sounds a bit indulgent, perhaps it’s because Amos regards classical music, not alt-rock or pop, as the more liberating genre. “I have been fascinated with Irish mysticism for a long time but haven’t been able to use it because pop music doesn’t allow that. Pop music is very strict as far as they want the chorus to happen quickly, you can’t really develop narrative all that much.

“Night of Hunters was more liberal in form – in other words, you could build a sonic cathedral instead of, imagine, a log cabin or a beach house.”

But did Amos find it constrictive, as one of the great woman pioneers of contemporary music, to create a new work exclusively from the compositions of dead white males? “When I chose all the music I listened to what each piece had to say, and I found the ones that made the record were more than willing to be a part of a 21st-century story of a woman," she says.

“Growing up at the Peabody when people would say ‘the three Bs’ you know – whoever they are, Bach, Beethoven, Brahms… It wasn’t Amy Beach, okay, it just wasn’t. But for Deutsche Grammophon to approach me as a woman and say, ‘with our blessing, go mess with the masters, make it great’, was an opportunity to say we’re going to tell a story about a woman, and her psychological process, and we’re going to use the ingredients to form a marriage between male and female as well. I’m taking some of their DNA and making a new being.”

Night of Hunters is out on Deutsche Grammophon on September 23. The album is reviewed in the October issue of Limelight, available from September 21.

TRACKLIST

SHATTERING SEA:

1) Variation on: Charles-Valentin Alkan (1813-1888): Prelude Op 31 No 8 Song of the Madwoman on the Sea-Shore